Control mechanism



L. J. MOULTON CONTROL MECHANISM s ept. 1, 1953 4 Sheets-Shet l Filed may2o, 195oA KRO dgl mml . IN VEN TOR. Lw/ Jackson Maul ro/v BY rw( w r1T-romvg y mlm Sept. l, 1953 J. MouLToN CONTROL MECHANISM Filed May4 20.1950 4 Sheets-Sheet 2 l yloa' IN V EN TOR.

LL 0 vp Jncmfo/v Moz/L ra/ Sept l, 1953 1 L. J. MouLToN 2,650,580

CONTROL MEcHANIsM' Filed May 20, 1950 k 4 Sheets-Sheet 3 Sept-1 1953L... J. MouLToN 2,650,580

CONTROL MECHANISM Arron-MEV Patented Sept. l, 1953 CONTROL MECHANISMLloyd Jackson Moulton, Mentor, Ohio, assignor to The Marquette MetalProducts Company, Cleveland, Ohio, a corporation of Ohio Application May20, 1950, Serial No. 163,115

(Cl. 12B- 103) 8 Claims.

The invention relates to an improved control mechanism for internalcombustion engine driven electric generator systems and particularlysuch systems as are used to drive the traction motors of locomotivevehicles, thereby indicating the general object. The invention providesa form of unitary control mechanism for the internal combustion engineand its generator, so that notwithstanding large variations in tractionmotor power demand the engine and generator are enabled to operateefficiently within safe load limits and at selectable engine andgenerator speeds suited to the` variations in load or power demand.

The invention, still more specifically, provides an improved means foreiecting adjustment of engine speed setting in one or more enginegenerator system units in accor-dance with predetermined remotelyselected signals or signal combinations, indicating a further object.

A concomitant object is to provide a relatively simple servo controlsystem including two effective interconnected relatively intersectinglevers, one containing two input points adjustable as functions ofremotely energized signals and the other containing an output point forconnection to a servo, the points or the axes of the levers establishinga floating plane, said effective levers being thereby combinable ifdesired into a single simple lever member spaced points on which can beused as output `and relay actuating connections.

Another object and feature of the invention is the provision of animproved automatically acting engine shutdown control, the operation ofwhich is normally responsive to .engine lubricating oil system failuresbut which is restrained from operating for a sufficient period to enableroutine starting of the engine (e. g. at idling speed) and which alsoprevents `the engine from continuing to operate in the event thelubricating oil system is 'not functioning properly a predetermined timeaiter starting.

In connection with detection of engine lubricating oil system failuresan object is to provde mechanism for variably opposing the action oflubricating oil pressure on the detection means with a force which issolely a function of the positioning of a speed setting servo mechanismof the engine governor,

Another object is to provide an improved hydraulically operating,remotely controllable speed setting mechanism for the engine speedgovernor, which mechanism normally functions .to limit the `rate atwhichspeed setting ,adjustment can be effected through remote controlwhile enabling rapid decreased speed adjustments to be effected asrequired by large changes of speed setting in the decreased speeddirection.

Other objects and novel features will be explained in, or will becomeapparent from the following description of the illustrative embodimentsshown in the accompanyng drawings wherein:

Fig. l is a schematic view showing the principal elements of the systemand mechanism hereof including a vtypical hydraulic relay governor forthe engine, electrical load control hydraulic mechanism coupledtherewith and one form of enginelubrication-oil-system-failureresponsive shutdown means foll the engine.

Fig. 2 is a schematic View corresponding in part to Fig. l showing amodified oil-systemfailure-responsive-mechanism.

Fig. 2a is a detail View of a v alve mechanism shown in Fig. 2.

Fig. `3 is a `diagrammatic perspective View showing the positionngsystem hereof by Whch equal movements of a plurality of solenoidarmatures may be selectively used and be permutated to produce thedesired number of positions of a single output servo element of thesystem.

Fig. 4 is a perspective view of one physical arrangement of partsessentially according to Fig. 3.

Fig. 5 is a similar View showing a somewhat different arrangement anddesign of parts.

Fig. 6 is a plan View of the speed setting and other mechanisms hereof`as applied to such hydraulic relay speed governor as shownschematically by Fig. 1.

Fig. 7 is a sectional view of the governor and associated mechanisms.

`Camera! purpose The invention as one aspect thereof provides a systemfor efficiently and -safely controlling the loading adjustments of aninternal-combustionengine-driven electric generator for rail locomotiveservice, largely through operation of the engine governor in response tospeed change detection thereby, in accordance with varying power demandso n an .electric traction motor or plurality of motors supplied withcurrent by the generator. i

The engine governor G, as schematically shown in Fig. 1, is of thehydraulic relay type arranged for isochronous operation, and has a fuelregulating servo .piston mechanism F, pilot valve P and a speed setting.means includingV remotely controllable actuator mechanism (see DF Fig.3) for a hydraulically operated speed setting servo mechanism S, allmore fully described later. The various mechanisms of Fig. l are shownin positions occupied when the engine is in operation at idle or lowspeed. The various iiuid operated mechanisms are shown, for convenienceonly, as having vertical axes.

Electrical load control In Fig. 1, at upper right, a well known type ofhydraulic mechanism is indicated at El for adjusting the electricalloading or load carrying capacity of the generator (not shown) as byvarying its eld excitation resistance. The vane 2 of reversible loadcontrol motor I is moved as indicated to increase generator excitationand thereby increase its electrical loading when operating nuid isadmitted to the motor I through line 3 and removed therefrom throughline E.; and the opposite effect follows reverse routing of fluid andreverse indicated movement of the vane (decreased excitation, decreasedloading).

Operating fluid for the electrical load control motor I may convenientlybe supplied from the lubricating oil system of the engine (not shown) asthrough a line 5 which leads to an inlet chamber 6 of a load controlvalve 'l having a multiported sleeve 8 and axially shiftable plunger 3with lands sa and Sb normally closing outlet/inlet ports connectedrespectively with the motor huid supply lines 3 and 4. The rate ofoperation of vane motor I may be controlled for maximum 'accelerationconsistent with equipment safety by throttling the exhaust uid from thevane motor as by individually adjustable needle valves Ita and I Ia inexhaust fluid lines IIl and I I connected with respective end portionsof the valve sleeve i3 and vented to an atmospheric pressure or enginelubricating oilrsump as at I2 between the needle valves.

The load control valve 1 is actuated by an intermediate portion of afloating lever Ill through an adjustable connection I5 therewith. Saidlever is connected at one end to the speed setting servo piston ZI ofmechanism S and at the other end, adjustably at i3 to governor servopiston tail rod 24. Valve 1 is normally maintained in the illustratedneutral position by the floating lever it. For a given speed setting, achange of generator load causes valving motion of the load. controlvalve by normal governor fuel regulating servo motion. The load controlvalve 1 is so connected to the load control vane motor I that action ofthe motor is such as to counteract the generator load change that hastaken place. This vane motor action will continue until, through normalgovernor action, the governor fuel regul'ating servo F has returned theload control valve to its neutral position.

In event of a change in speed setting servo adjustment (mechanismrS)valving action of the load control valve 1 will cause through the loadcontrol motor I, a change of generator loading in the same direction asthe speed change until, through normal action of the governor fuelregulating servo the load control valve is returned to its neutralposition. Thus for each position of the speed setting servo with aneutral load control valve position, there is a corresponding governorfuel regulating servo position.

Hydraulic relay governor The engine fuel regulating governor G- as willbe more clearly apparent from Fig. 7 may be considered as constitutingthe basic environmental portion of subject system, partly in that thegovernor assembly, as is usual, has its own hydraulic pressure source(e. g. pump 3I and springe loaded accumulator 32, of Fig. l) whichsource serves all other hydraulically acting mechanisms not yetdescribed and may also serve the electrical load control motor l.

The governor G has a speed sensitive mechanism 2,3 including iiyballs 34on a rotary ballhead assembly 35 driven as will be explained, the yballsacting on the plunger 35 of pilot valve P in non-rotating pilot valvesleeve 31. Gutward action of the iiyballs is opposed by a Speeder spring33 connected to the pilot valve plunger 36 through a thrust plateassembly 39.

For minimization of static friction in the essential elements of thegovernor pilot valve and ilyballs turn the valve plunger 316 in itssleeve 31 through the intermediary of the assembly 33 substantially asin Kalin Patent 2,219,229, issued Cctober 22, 1940. An antifrictionbearing 39a, Fig. 7, is interposed between thrust plate assembly 39 anda non-rotating collar 39h connected to the lower end of the speederspring as in said patent. Speed setting servo piston 2| of mechanism Sadjusts the Speeder spring 33 to set the engine speed by a succession ofdirect actions on said spring-raising of the piston resulting indecreased engine speed settings and lowering resulting in increasedspeed settings.

Hydraulic fluid from the pump and accumulator system (hereinaftergovernor pressure oil or governor oil) is continually admitted to thetop (smaller area 23') of the governor servo or power piston 23 throughline dil-portion Ilia thereof. In neutral or equilibrium position of thegovernor pilot valve plunger 36 oil is trapped in contact with the lowerlarger side 23 of the power piston. Fuel on movement of the power pistonresults from downward pilot valve plunger movement admitting governoroil through ports I of pilot valve sleeve 31 and line 42 to the largerpiston side 23; and Fuel ofi movement results from upward movement ofsaid valve plunger, thereby spilling trapped oil from line d2 togovernor sump through ports 43 of pilot valve sleeve Feedback fromgovernor power piston 23 to the governor pilot valve P is shown in theform of a hydraulic compensation system arranged for isochronousgovernor operation. The power piston 23 pumps compensation oil throughline i5 to and from the working chamber of a receiving compensationpiston 46 attached to the pilot valve plunger 36 by a coil spring 41;and an adjustable leak-olf for compensation oil is provided in thesystem at 48.

Speed setting servo system The governor speed setting servo mechanism Sincludes a speed setting servo pilot valve mechanism 55 shown in Fig. 1at the left of the governor pilot valve. Valve mechanism 50 comprises avalve sleeve 5I and valve plunger 52 slidable therein. A relativelysmaller (lower) area 2l of the speed setting servo piston 2l iscontinually exposed to governor pressure oil through a line connectedwith line portion 43a. of line 40. Line d@ is continually connectedwith'accumulator output line 55 through a cavity 54 around valve sleeve5I. A valve chamber 56 within the sleeve 5I (defined in part byrelatively upper and lower effective lands 51 and 58 of the Vvalveplunger) is continually connected, via line 59,

with the upper relatively larger effective area 2l" of thepiston2l.

The speed setting servo pilot valve mechanism 5U is shown in a neutralposition and it will be observed that upward movement of the plunger 52can cause a pair of slots 51a of land 51 (one slot shown) to open ports60 and permit governor pressure oil from line to be supplied throughline 59 to the larger (top) side of speed setting servo piston 2| andcauseJ downward movement of the piston. Similarly downward movement ofthe pilot valve plunger 52 (opposing return spring iii below theplunger) enables paired slots 58s.'. in land 5B (one slot shown) to opensumpconnected ports (i2-resulting in spilling oil trapped in lineEil-thereby to cause or enable upward movement of speed setting servopiston 2 i through the continually effective governor oil pressure onlower piston face 2|.

Primarily to minimize static-friction-forcerestraint on valving relativemovement of speed setting pilot valve elements 5I, 52 and,concomitantly, to control the rate of movement oi the speed settingservo piston 2l and of a hydraulically acting shutdown mechanism actingthrough the valve mechanism 5S while enabling use of undiminishedgovernor oil pressure (mechanism later explained) the pilot valve sleeve5i is continually rotated during governor operation. (e. g.) keyed toone of the two gears which form the principal elements of the governoroil pump 3 i. The sleeve 5i, in turn, through a set of mating gears 5 ia at the top of the valve sleeve, drives the ball head 35, andtherethrough the governor pilot Valve plunger 35. Rotation of the sleeveEl can effect fluid flow `rate control in a variety of different waystwo of which are shown (Fig. l and Figs. 2, 2d).

The speed setting servo rate control according to Fig. 1 (assumingrotation of the pilot valve sleeve 5i and that plunger 52 is suitablyheld against rotation) is illustrated by supposing that plunger 52 israised from the illustrated neutral position (for increased speedsetting by application of governor pressure oil to upper chamber ofservo piston 2i whereupon it is apparent that the slots 5l@ of land 5lcan only register with the ports @il on` each partial rotation of thesleeve, causing interrupted` admission or spurtwise iiow of governor oilinto line 5S. Similarly, when the valve plunger 52 is lowered a limitedamount (for decreased speed setting) slots 58a of land 55 interruptedlyalign with the spill ports t2 for spurtwise i-low through the valve.

If more than the limited lowering movement ci the speed setting servopilot valve plunger 5i. takes place, then the entire top edge of land 53controls spill ports 62, resulting in rapid travel of the speed settingservo piston toward the minimum speed setting and shutdown-effectingpositions. Shutdown action of said piston 2l (explained later) isthrough the intermediary of the governor pilot valve P.

Speed setting servo system actuator receiving elements (e. ,.g.solenoid-lever combina- The sleeve 5l for that purpose is tions) arediagrammatically shown in Fig. 3 and will be described later.

ln Fig. 4 (illustrating essentially the physical arrangement accordingto Figs. 6 and but not in scale therewith) the servo mechanism S isrepresented by servo piston 2l and relay valve plunger 52 as pivotallyconnected at respective .spaced points 65 and B6 along the effectivelongitudinal axis of a floating lever 68 one end oi which is pivotallyconnected at point 69 with a differential lever lo. Point 55 is theoutput point of the system, and the input points are represented at 'iland 'i2 which are preferably at the opposite ends of the differentiallever lil. It will be lapparent that the output point 55 in conjunctionwith the input points ll, 'l2 (likewise the longitudinal aires of theeiective levers) cletermine a floating plane.

Signal receiving members are shown in the form of solenoid-operatedgenerally parallel levers 'i3 and ill one end (e. g.) of each ci whichis connected to a respective `end (points il and l2) of the difierentiallever 'Hl as by clavie-like joint elements (e. g. pins `and elongatedslots) with suitable provision for vertical adjustment relative to thearmature of the solenoids, described later. The floating lever 68 mayalso have provision for vertical adjustment of point 55 with respect tothe relay valve plunger. In Fig. 4 a pivotal connection at point S5between differential lever 'it and iloating lever 58 is indicated as aline bearing (like a hinge) but no provisions for relative pivotingbetween levers and iii is actually necessary as will be explained.

In Fig. 5 approximately the essential arrangement or Fig. 4 isrepresented by the combining of the floating lever 68 and diierentiallever 'iii into a single member shown in the form of a substantiallyrigid universally iioating plate 15, e. g. sheet metal stamping, theeiective lever aries and essential connection points being generallyindicated by the same characters as used in l but primed. Point S9' doesnot act as a pivot; and, in order to allow the necessary universalfloating movement of the plate '15, a spherical joint is substituted forthe assumed hinge joint connection of lever 58 to the relay valveelement 52 of the servo system. The connection at 55' between lever 68and the servo piston 2l is a suitable point bearing. The plate i5 can bemaintained in freely operating position and the necessary bearingelements held in working contact by provision of combined action (e. g.looped leaf) springs 'il attached to the plate and some fixed part ofthe governorspeed-setting mechanism housing or supporting bracketportion thereof.

In 3 the remotely-controllable signal receivers more or lessdiagrammatically represented as four solenoids A, B, C, and D, thearmatures of which are assumed to be appropriately connected to thelevers i3 and it for push or push-pull operation thereof. The number ofsolenoids is already established in practice and also their manner ofcontrol (order and permutation o energization and deenergization). Thesolenoid armatures normally have equal length strokes.

Signal permutation Subject system uses permutation of the four equalstrokes of the solenoids A, B, C, and D to effect all the necessaryincremental positioning of the speed setting servo piston 2| as desiredfor diesel-electric locomotive engine control at the present time. Theclevis type connections at point 'I8 in Fig. 4 between the armatures ofsolenoids B, C, and D and the levers I3 or 14 are partly for holding thelevers in proper working planes, and those armatures pull upwardly onthe levers at the connection points against the resistance of suitabledownwardly acting springs (not shown) associated with the solenoids.Solenoid A acts downwardly when energized (against an opposingspring,not shown), through a clevis 'i8 or any other suitable connection (e. g.point bearing) against the lever i3. The armature, lever connections,and positioning springs serve alternately as fulcrums as already knownto the art.

Selective energization of the solenoids is effee-ted by operation of anelectrically conductive contacter drum element or plate such asrepresented at le, Fig. 3 prcled to establish and disestablish currentin respect to the solenoids A, B, C and DV in predetermined combinationsequence in accordance With relative positions of element 73 and the rowof solenoid-etc.con nected contacts 'i9' as Well understood in theelectric controller art. The positions for engine shutdown (stop), forstarting (idle) and the various steps for increased speed settings: #2,#3, #4, etc., (#1 being for electrical load control purposes only), areindicated on Fig. 2, adjacent the drum element 19. Shifting of saidelement through stcp-contacting position and the various indicatedcontrol steps energizes the solenoids in the following order: D; none;None; A; C; AC; BDC; ABCD; BC; and ABC. In indicated step #l thegenerator excitation is energized and remains energized for all thesubsequent steps.

By energizing and deenergizing the four solenoids A, B, C, and D allpossible input motion subdivisions (three subdivisions for each pair ofsolenoids) are established. When both solenoids A and C are deenergizedthe servo control or differential lever input point position of lever 13is at Fig. 3. Similarly solenoid A on and C ofi results in servo controlsystem input point position A: with A oir and C on: input point positionC results; and with both solenoids A and C on input point position A C".

Similarly, combinations ofaction and inaction on part of solenoids B andD result in the indicated input point positions 00, B", D and BD at theopposite end of the differential lever lil.

rlhe resulting combinations of input point subdivisions operate throughthe differential leverV lil to provide a plurality of net inputsubdivisions at point 69 of the eiective levers 68, 10. Nine equal netinput subdivisions may be obtained by location of net input point 69 atone third of the distance along the diierential lever between the inputpoints 'H and l2 and by selecting appropriate combinations of inputsubdivisions. Seven equal net input subdivisions are used between steps#l and #8, two of such obtainable subdivisions being used for engineshutdown.

In Fig. 3 it may be observed that the ampliiication ratio of the servosystem is determined by the ratio of effective feedback lever lengthelements 66-65:66B9, the embodiment thereby resulting in a reverselyacting feedback lever. If a direct acting feedback lever were to be usedthe relay actuating point G6 would be located along an extension of theeiective feedback lever beyond point 69; but the ratio of the distancestti-65:65-89 would still determine the amplitying ratio.,..

Signal actuated valuing It will be apparent from the above that as thecontrol drum or contacter element 19 is moved, as from idle through thevarious speed setting increment steps #2, #3, etc., the speed settingservo piston 2 I, notwithstanding the rapid action of the solenoids,will be moved gradually through the corresponding positions due to thelow rate of fluid movement (interrupted, spurtwise ilow) through thespeed setting servo pilot valve 50 via the slots 57a in the plunger land5l. It will also be apparent that in the decreased speed settingdirection of operation of the pilot valve 50 slow, stepped speedadjustments result in low rate servo movement by reason of theflow-interrupting action of the lower land slots 58a. If the plunger 52is moved downwardly far enough to uncover the ports 62 by the entireupper edge of plunger land 58 non-interrupted, hence more rapid, flow oftrapped fluid from above the speed setting servo piston 2| occurs. Suchrapid ow may result from rapid control drum operation in thereduced-speed-setting direction or through the agency of several enginestopping devices as will be described. The engineer or operator cannotby rapid control drum operation vary the rate at which increased speedsetting operation of servo piston 2l will occur.

Speed Setting mechanism adjustment Because it is a diiiicult matter tomanufacture speeder springs e. g. 38 Fig. 1) so that springs ofdifferent, supposedly identical, governors are exactly alike anadjustment of the idle speed setting position of servo piston 2l may beaccomplished by variations in the equilibrium or neutral position ofspeed setting pilot valve 50 as determined by action of the varioussolenoids on the eiective lever system of Figs. 3, 4, and 5,

For example, the stem of the pilot valve plunger, as in Fig. 5, may beoperatively lengthcned or shortened by suitable means as suggested andlocked in position after the idle setting or" piston 2E is found toobtain the desired idling speed of the engine. An operative equivalentof the adjustment just described, in theV case of Fig. 4,canrconveniently be accomplished by making the two portions 69-71 and69-12 as separate sections hinged together at point B9 for relativeadjustment about the hinge axis (see adjustment device iiga, Fig. 7)thereby enabling movement of all the net input positions up or downwithout changing the total travel represented by the net inputsubdivisions.

In addition or alternatively, in order accurately to adjust the Speederspring for predetermined governed speeds, having in mind that veryminute differences in stroke lengths on part of the various solenoidsarmatures (strokes being short) may be reiiected in importantinequalities in speed setting step increments of the servo piston 2l,the solenoid armatures are made individually adjustable (adjustmentmeans not shown, being of known construction) at one end or the other ofthe stroke of each. Adjustment of the beginning points only ofrespective solenoid strokes is usually suicent in order to obtain thenecessary servo step increments for accurate speed setting.

Engine lubrication system failure shutdown (automatic shutdown) Subjectsystem automatically eiects shutting down or the engine in event (a) theengine lubricating 011, system output pressure drops to a predetermined,i. e. dangerously low, value in relation to engine 'speed and (b) thelubricating oil pump intake absolute pressure drops to a predeterminedabnormally low value (excessive pump suction). As previously indicated,however, the lubricating `oil failure responsive shutdown operationneeds `to be delayed in order to permit routine starting; and theengineer or operator should be enabled to re-start the engine aftershutdown and operate it at low speed for brief periods such as willenable study of the cause of lubricating oil system failures.

Engine shutdown (Fig. 1) can conveniently be accomplished throughhydraulic adjustment oi the speed setting servo piston 2| to a topposition (not shown) whereby the governor pilot valve plunger 36 isphysically raised and maintained in a position such as will cause thepressure of trapped oil below the fuel adjusting power piston 23 to bedissipated quickly, A suitable means for so accomplishing shutdown isthe provision of ashutdown rod such as shown at 80, Figs. l and 7extending freely through an axial bore of the piston `2|, through theSpeeder spring 38 and to the non-rotating, spring-supporting collar 39h,the bearing 39a thereby providing a Asuitable swivel connection betweenthe shutdown rod 80 and the valve plunger. The upper end of the shutdownrod has an axially adjustable abutment 82 (pair of threaded nuts, Fig.'1) positioned for engagement with the upper stem portion 83 of thepiston 2| which, when that piston is caused to move upwardly apredetermined distance above its "idle speed setting position, pullsupwardly on the governor pilot valve plunger 36 through rod |39 `causingcutting oli of engine `fuel through already described means.

Engine shutdown control in event of engine lubrication oil systemfailure (and when hand shutdown operation at the governor isnecessitated for any reason) is accomplished by long stroke downwardmovement of the speed setting servo relay valve plunger 52.

Ihe oil-system-failure-responsive apparatus, indicated generally at LF,upper left Fig. l (LF in Fig. 2) controls a valve 86 whichdivertsgovernor oil from -accumulator-connected line 55 as through lines 99,88a, described later, and line 85 to the working chamber H of anoil-failureshutdown motive unit I |0 which, through a lever H8 and lostmotion connection |29 (also de- 'scribed later) is capable of depressingthe speed setting servo relay valve plunger 52 a considerable distance(i. e. sufficient to uncover pilot valve spill ports 82 by the entireupper end of plunger land 58).

Time delay (of shutdown) for engine starting and testing Operating iluidfor shutdown motive unit ||0 is routed fromgovernor--accumulator-connected line 55 to lubricating-system-failureresponsive valve 86 through the `annular chamber 54 around the speedsetting servo pilot valve sleeve ports 88 and 91 thereof whichintermittently register with elongated axial slot 98 (or grooves) in theplunger 52 as the sleeve 5| rotates, and a line having continuallyinterconnected portions 89 and 88a, thereby supplied with oil spurtwise.Portion 99 is continually open to Valve sleeve ports 91, and portion 88aleads to a port |00 of valve 85 which port is normally closed. Therotating relay valve sleeve 5| thus maintains one source of supply ofoperating pressure for shutdown motive unit which, upon actuation ofvalve 86, ilows to said unit through line T at a delinitely controlledrelatively slow rate. ASuch slow rate supply of uidenables the engine'to be started, but only at idle or low 'speed setting, "by delayingshutdown action for a period'such as required for normal enginelubricating oil pressure to become established. The rate of action ofshutdown motive unit |I0 can be further varied by `an adjustableleak-01T 'valve I I3 situated between valve 86 and said unit (shown inline 05).

For speed `settings other than low or idle aspurtwise-flow-circumvcnting `or by-pass valve it (lower left describedlater) is operated by the speed Vsetting servo mechanism S `to sup-plythe line d8a leading to valve 88 continuously with governor oil for morerapid shutdown action upon functioning `of thevalv'e 86 to open line'89a to line 85.

Engine VZulm'cating system failure detector Lubricating `system failureresponsive mechanism LF, in addition 'to valve 86, comprises twopressure detecting :motive units 81 and 88 embodying respective elasticdiaphragm -members 89 and 90 in sealed chambers 89', 89" and 90', 98formed between separable casing portions 8| and 82. Chamber portion 88is-connected to the pressure side of the lengine lubrication ysystem atopening 93, and `chamber `portion is similarly connected to thesuctionside ef said system at 94. The engine shutdown operation isaccomplished through `actuation of the valve 88 by whichever one of thedevices 81 or 88 detects a failure or undesired condition of thelubricating system.

In order that the lubricating oil pressure as imposed on diaphragm 89`may vary with engine speed without initiating shutdown, and as -a meansof obtaining shutdown initiating force, a counterbalancing or opposingpressure `varying with engine Speed (actually with speed setting) ismaintained in `diaphragm chamber 89" by, for example, device |40comprising a spool-like plug |02 slidable in sleeve I 30 and a controlspring |48 operative on the plug to maintain adjusted pressure indiaphragm `chamber 89" through a line |88. Pressure maintained in saidchamber insures operation `of valve 85, when lubricating oil pressurefails, in unblocking port |00 leading to shutdown motive unit ||0.Device |00 will be more fully described under the heading VariedOpposition to Lubricating Oil Pressure.

Port |00 or valve 88 is formed in a suitable sleeve 88' dening the`falve chamber, and said port is normally blocked by land |03 of valveplunger |02 arrangedfor operation interchangeably by detector units 81and 88 through the intermediary of a lever |04 pivoted at |05 to one endof the plunger |02 and push `rods |01 and |08 connected to respectivediaphragms 88 and and bearing on respective ends of said lever.

The diaphragms 89 and 98 `have coil springs |01' and |08 acting throughthe diaphragm center supports on respective pushrods |01 and iii-8. Coilspring 01 acts in a direction to maintain the pushrod |01 of diaphragm89 against a nxed stop, as does adequate lubricating oil pressure onthat diaphragm. A spring 09 acts on the valve plunger |02 ofvalve 86 ina direction to cause the plunger |02 Vand its operating lever to followthe pushrods |01 and |08 and unblock port |00 when either or bothpushrods moves or move in a direction indicating a lubricating oilsystem failure. `Spring |08' of the excessivesuction-responsive unit88'is designed to resist movement of diaphragm 90 out of its normal(illustrated) position except when excessively high suction occurs inchamber portion 99. Spring |08 enables the pushrod |08 to act as afulcrum for the lever |04 when the diaphragm 89 is moved (during thedescribed low lubricating oil pressure conditions) to initiate theengine shutdown operation through action of valve 35 and motive unit|I0. Similar fulcrum action of the pushrod |01, when diaphragm 90 movesto initiate shutdown, is enabled by pressure of lubricating oilV againstthe diaphragm 89 assisted by spring |01. Simultaneous action of bothdiaphragms also initiates shutdown assuming appropriate pressure in line|44 as partially described assisted by spring |09.

Passage 95 in diaphragm casing section 9| connecting the lubricating oilsystem fitting-receiving holes 93 and 94, is (during operation ofsubject system) closed by a valve plug 95. The passage 95 (with valve 95open) permits the lubricating oil to be introduced into the chamber 99'and bled into chamber 95 along with any air that might otherwise betrapped in contact with diaphragm 89.

Assuming action of either or both diaphragme 89 and 90 as describedabove, resulting in unblocking of port of valve 86 by valve plunger land|03, the movement of the plunger by reason of its land closes asump-connected outlet or spill port 2 in bore I0|. Assuming further thatthe engine is operating at idle speed, governor oil from line 99a at acontrolled or relatively slow rate is forced to ow in the line 85 andbegins to move piston I4 of motive unit 0 against the resistance of apiston return spring I|5 in a direction to cause the piston to depressan upstanding pushrod IIS connected to the shutdown control lever IIB.

The lever IIB has a iixed fulcrum ||9 at one end and the opposite end ofthe lever, as previously indicated, has a two-way lost motion connectionwith the stem of speed setting servo relay valve plunger 52. Theconnection |20 of the lever, incidentally, is designed to prevent thevalve plunger 52 from turning with its continually rotating valve sleeve5|. Lever I I8 has a positioning spring |22, which may be associatedwith the pushrod IIB, to return the lever to its nonoperating positionclear of the lost motion abutment surfaces |20' and |20I of the pilotvalve plunger so that movement of said plunger by the signal-receivingelectrical mechanism will be substantially unrestricted.

The normal distance between the pushrod IIS of shutdown motive unit I|0and its piston |I4 is such that the spurtwise flow in line 99 requires asubstantial period of time (which may be variably adjusted by valve I I3as already mentioned) in order to accomplish engine shutdown afterVinitiation of that operation by a diaphragm unit 81 and/or 88.

It will be recalled that downward operation of the speed setting servopilot valve plunger 52 for more than a small part of its possiblemovement results in fast upward operation of speed setting servo piston2| to the top of its possible stroke and operation of engine shutdownrod 80.

Varied opposition to lubricating oz'Z pressure As already mentioned, thetime delay (prior to shutdown) afforded by spurtwise supply of governoroil through line 99 is made available only in the idle speed setting ofthe servo piston 2|.

Said' piston has'a rigid arm |34 thereon arranged to control theposition of the spurt-circumventing or by-pass valve |35, shown in Fig.l as comprising an upwardly spring biased valve plunger I 31 in portedsleeve |39` already partially described. The plunger |31 has a land |38which in the idle or low speed positions of the speed setting servopiston blocks ports |39 connected to governor oil pressure (line 55a).In all high speed settings the plunger |31 is depressed bypiston-connected part |34I to uncover ports |39 so that governor oil canbe caused to flow steadily through line portion 99a etc., to theautomatic shutdown piston unit IIO as soon as plunger |02 of valve movesto unblock feed port |00.

For each engine speed there is a particular minimum safe lubricating oilpressure, the minimum increasing with engine speed. Therefore, theaction of the engine-lubrication-system-failure responsive shutdownmechanism is modified by the speed setting servo mechanism throughoutthe range of speed setting steps from #2 to The valve sleeve |36 ofvalve |35 also serves as the body of the pressure control device |45action of which was earlier outlined and which appropriately modifies orvariably opposes the action of the engine lubricating oil on thediaphragm 89 in accordance with engine speed. The spool-like 'floatingplug or plunger I4I of said. device |40 has a lower land |42 controllingadmission of governor oil from line 55h at sleeve` ports |43 into theline |44 communicating with. the bore of the sleeve |36 below theiioating plug through passages |45 therein and around the neck of theplug. The line |44 as already 'stated leads to diaphragm chamber 88" oflubricatingoil-pressure-responsive motive unit 81. The top land |46 ofthe floating plug normally closes spill ports |41 leading to governorsump and the plug is biased downwardly by a coil spring |48 which,incidentally, is connected to the lower end of spurt-circumventing orby-pass valve plunger i9? and to the floating plug by coils of thespring acting as screw threads. The space enclosing the spring |48 issuitably vented to sump.

By the above described arrangement governor oil is permitted to occupythe line ififl e tphragm chamber S9 at pressure determined y thecompressive resistance of the spring idd wr' i. opposes upward(port-closing) movement oi" the iioatingY plug through accumulatingpressure therebelow acting on its lower end. As the valve plunger |31 islowered by the speed setting servo piston 2|, in calling for increasedengine speed, increasing pressure in line |44 is requiredhydrostatically to close ports |43. Therefore the pressure in line |44,as required to modify the described automatic shutdown action, is solelya function of engine speed setting. The action oi the mechanism |40 isnot affected by any other part of subject system, which is also true ofthe modied arrangement (Fig. 2) to be described later.

Hand shutdown and alarm switch The lever I |8, engine shutdown action ofwhich. was described abovehas a linkage including two part rod |24secured to it for operation by a lever |25 having a manually accessiblehandle portion |25 externally of the governor case. The lever |25 asshown is in the nature of a bell-crank having an arm |29 connected tothe actuator arm |21 of an electric spring toggle switch |21 by whichanalarm circuit (not shown) is operated concurrently with automatic engineshutdown due to lubricating oil. system failure. The toggle springlatches the lever in the indicated stop `position aswell as its runposition. The switch |21 is operated Ain response lto shutdown action ofshutdown motive Vunit iil through the intermediary of a yielding portionof the linkage which portion, as shown, comprises a spring |25 in ahousing |29 forming the upper part of rod |24.

The housing |29, through a shoulder .ist on rod |24 is hel-d by spring|28 in operating `abutment with the lower portion of the rod positivelyto transfer hand shutdown manipulation of the handle portion |25 oflever |25 to the lever H8. The spring |23 enables the lubricating-oilsystem-failure-responsive motive unit il!) to override any attempt by theoperator, through inanipulation of handle 25', to maintain the engine inoperation indenitely when the lubrication system is not functioningproperly.

When the speed setting servo piston 2|, as a result of either automatic(lubricating oil system failure) or hand shutdown operation (lever |25)moves to its shutdown-rod-lifting position said piston 2|, through itsarm 34, allows spurt circumventing valve plunger |251 to `lift and withit the spool-like plug |41 of the lubricating-oilpressure-opposingmechanism i156 by relievingT the force of its spring |48. Pressure inthe line la leading to diaphragm chamber 89 thereby `immediately fallsto negligible value (spilled at plug sleeve ports Ml) as the handshutdown rod l24 and the lever l `become latched by switch `arm |27 inshutdown position. Thereupon, in the absence of lubricating oilpressure, the spring |01 which acts upon the lubricating oil pressureside of the diaphragm 89 returns the valve plunger |02 of valve 8B toits initial `illustrated `position in which oil that has accumulated inshutdown piston unit liu can `be spilled through vent port 2, whereby toenable the engine to be started up again.

After the described automatic shutdown or hand shutdown operation hasbeen accomplished the handle |25 must be returned to its run position inorder to free the `speed setting pilot valve plunger 52 from restraint`by shutdown control lever ||8 at its lost motion connection |20.

If it is desired to eliminate the fluid spilling action of valve 86 atport ||2 the spring Itll' of mechanism LF can be omitted, in which casethe needle valve ||3 or equivalent leakoff means will determine a periodof rest, after automatic shutdown, before the engine can be restarted.

Modified lubricating oil system failure responsive mechanism As shown inFig. 2 the speed setting servo piston 2| is arranged mechanically toprovide for adjusting, in accordance with engine speed, the criticaloperating point at which low lubricating oil pressure causes engineshutdown through action of motive unit H0. As shown in Fig. 2 the speedsetting servo piston 2| has an operating abutment |55 for a lever |56pivoted at |51 -which lever acts through an arm |56 thereof to adjust acompression spring |50 bearing against the diaphragm 89 which is exposedto lubricating oil pressure .and in a direction opposite the action ofsuch pressure. The lever arm |56 acts against a tubular distance piece|6| forming the support for one end of the spring |60. The effectiveforce of the spring in the direction of shutdown-initiating movement ofthe diaphragm `89 is thereby increased with engine speed-i. e. the sameultimate effect as `obtained by the hydraulically acting pressurecontrol mechanism |40 of Fig. 1 `which is omitted from the systemaccording to Fig. 2 as may be observed in connection with modied timedelay fluid control circumventing mechanism 35a. The special parts ofmechanism |35a are identified by the same characters as those previouslyused, but primed.

With the `modified arrangement just described, force of spring .|60 ondiaphragm 89 is removed when speed setting servo piston 2| moves to itsshutdown-.rod-lifting position through interaction of pin |55 :and lever|56. Thereupon in absence of lubricating oil pressure the spring lillwhich acts upon the lubricating oil pressure side of the diaphragm 89returns the valve plunger |52 of valve to its oil spilling position tovent operat ing huid from unit H0.

As in the Fig. 1 arrangement -the diaphragm spring lul 4can be omitted,and controlled rate spilling of shutdown motive iluid through needlevalve |3 substituted.

Modified spurtwise ,fluid valuing Fig. 2 (lower right) `andcomplementary view F'ig. 2a illustrate `a modiiied speed setting servopilot valve and fluid rate control mechanism 50a wherein spurtwisevalving action for controlled rate movement .of servo piston 2| anddelayed shutdown action asalready described are obtained principally byrotation of the pilot valve sleeve 5|a with reference to .portformations intersecting the bearing bore for the sleeve.

rhe governor pressure oil supply line `portions 1li) and 4ta are shownas modiiied to the extent of being in non-intersecting relation to thebearing bore for sleeve 5|a but connected thereto as by a passage 4Gb.The passage registers intermittently with one or more longitudinalgrooves 98a in sleeve 5|a (one groove shown) which in turn registers orregister intermittently with a port portion 99h of line 99 for spurtwisecontrol of governor oil .in respect :to shutdown `motive unit l0. Radialports Ella of the valve sleeve intersect the longitudinal groove `98aand are controlled by plain edge 57h of the upper valving land oi pilotvalve plunger 52a for supply of governor oil spurtwise to feed line 59of the speed setting servo mechanism when said plunger is raised in:calling for increased speed settings.

Radial spill ports 62a in the sleeve 5|a (one shown), controlled byplain edge 58h of the valve plunger 52a, register intermittently with acooperating sump-comrnunicating port 52h for single step (controlledrate) decreased speed setm ting operation of the valve plunger, hencethe speed setting servo. Farther, i. e. abnormal, downward movement ofthe valve plunger 52a (very small amount in actual practice) uncoversradial ports 52o of the sleeve 5ta which constantly communicate withgovernor sump, through conventional passage means as illustrated, forhigh `rate `movement of the speed setting servo in `the `decreased speedsetting direction and for shutdown.

Pneumatic speed setting actuation Fig. 2 also illustrates`diagrarnrnatically the manner in which elastic duid pressure for remotecontrol of the speed 'setting servo mechanism can be used in place ofsolenoids. Unit 2li) is an elastic diaphragm assembly similar to thoseused for engine lubricating system failure detection and with apushrod2|| Vacting on theieedback lever E8 as at 2|4. Operating fluid issuitably introduced below the diaphragm 252 which has a return spring 2i3 opposing the action of the elastic fluid and which causes thefeedback lever St to follow the pushrod 2| Load control; transitionoperation As shown by comparison of Figs. l., 6, and 7 provision is madethrough a solenoid-actuated transition valve TV and transition piston Tin connection with the load control valve mechanism 'i to renderautomatic adjustment of valve 'i by the governor power piston mechanismF through the tail rod 24 and its connecting linkage temporarilyineffective during changing or traction motor connections by theengineer or operator.

During such changing of locomotive traction motor connections, thegenerator excitation must be reduced to some low value in order to avoidarcing at the contact points. The operators electrical control mechanismfor effecting alteration of traction motor connections is arranged toenergize the solenoid |79, Fig. l and operate transition mechanism T ina direction to cause the vane of the load control motor l through itsvalve i to move toward minimum excitation position. Reducedexcitationrrneans reduced engine load and as a result the governor powerpiston, to prevent overspeeding, moves to a low lfuel position throughaction of the governor ily balls 3d. Fuel decreasing motion of thegovernor power-piston-connected end of floating lever le would thereby,through normal operation of load control valve 1, result in the' loadcontrol motor l moving toward maximum excitation. Thus when the newelectrical connections are established the eng-ine would be overloadeduntil a proper balance between generator excitation and engine speed hadbeen established. To prevent suoli overloading normal load controlaction is made temporarily ineffective; and the vane motor I is causedto move toward minimum excitation concurrently with changes in thetraction motor connections.

As shown, Fig. |`l, transition valve mechanism TV has a plunger il!connected with the solenoid armature and operating in a suitable portedsleeve |12 connected as by a line |73 to the governor accumulator systemthrough pressure line 4ta. Ports |14 of the valve are controlled by adownward movement of a valve plunger land Il to divert pressure iiuid asthrough l-ine |19 to the working chamber of a piston |18 which isnormally retained in non-working position by a suitable spring |89. Theoperating rod iti of the transition piston |18, as shown particularly byFig. 7, carries an arm |82 adapted ultimately to abut and raise a crosspin |83 on the stem portion |84 of the load control valve plunger which,as shown, is coupled by a link |35, to the adjustable connection l5 ofthe floating lever |4.

When the solenoid is energized by the operators electr-ical controlsgovernor pressure oil ows `from the line |'|3 raising piston Ilii, asstated above; and when the solenoid l'iil is deenergized a suitablereturn spring of the transition valve TV moves the solenoid armature androd ill to init-ial position meanwhile dumping the operating pressurefor piston VEB through spill ports |36 leading to governor sump.

Referring particularly to Fig. '7 adjustable connection I6 is providedin order that when the governor power piston 23 is caused to move to its#l (excitation) position by the speed setting 'iii servo mechanism S,the load control motor will be moved either to maximum or minimumgenerator excitation position as required the type of locomotive serviceinvolved. Those two conditions are thus made available selectivelyduring installation of subject system by the described adjustment since,4in onev case the load control valve plunger 9 will through portcracking by land 9a, cause maximum excitation. and in the other, throughsimilar port cracking by land to, cause minimum excitation.

The governor power piston tail rod 24 has its upper end threaded at |93to mate with threads cf an adjustable sleeve I9! arranged to be moved upor down by sleeve portion |9l and locked in adjusted position as by nut|92. A tubular cross head |94 around the adjustable sleeve I9! issuitably maintained in axially adjusted position on said sleeve and theconnection I6 between the floating lever i 4 and tail rod 24 isrepresented as a pivot pin coupling the neat-ing lever to the cross head|94.

Balance point adjustment The adjustable connection |5 Fig. '7 betweenthe floating lever 4 and the operating rod |84 of the load control valveis provided in order to allow an adjustable relationship betweengovernor power piston travel and speed setting adjustment. Suchadjustment requires shifting of the point of connection between the loadcontrol valve plunger 9V and the iioating lever I4. Adjustableconnection i5, in construction, is essentialiy the same as theexcitation-adjustment between the tail rod 24 and iioating lever it,being a cross head |96 adjustable by a thread sleeve E97 along theiioating lever and capable of being locked in position as by nut |98aiter the proper balance point has been selected as determined by trial.Since adjustable connection i5 includes the link it is usually necessaryto perform adjustments l5 and I6 .simultaneously because the link iseffectively shortened as it is moved out of vertical position.

lt will be seen from Fig. 7 that both the excitation adjustment andbalance point adjustments are made easily available for manipulationthrough the top of the governor casing section 2&9 by removal of thecover `20| I claim:

l. In and for an internal combustion engine having a pressure operatedlubricating oil system, a hydraulic relay governor having ahydraulically operated speed setting servo mechanism including pilotvalve means and a servomotor controlled thereby to adjust speed settingsfrom low through a range of higher a hydraulically acting engineshutdown system including a shutdown motive unit said speed settingservo pilot valve means operating through intermittently registeringvaive passages to maintain a low rate supply oi operating nuid for theshutdown system whenever.` the servo is in low speed setting position, avalve mechanism connected for operation by the .speed setting servomotorand operating whenever the servomotor is in higher than said low speedsetting position to maintain a higher rate oi su ply olshutdown-system-operating iiud, a controi in the shutdown systemnormally blocking admission of operating fluid at either rate to theshutdown motive unit, and a fluid pressure operable device sensitive tca predetermined pressure condition ofthe lubricating oil system, in-

-dicating failure thereof, foropeni-ng said con- 'trolfvalve.` i

2. In ,and for 1 an internat combustion engine having a ipump voperatedlubricating -o'il system, a hydraulic relayV=governor for regulating theengine fuel input, an engine shutdown system including a hydraulicmotive 'unit operative to adjust the governor to block fuel input to theElflgne.` -mcanSpper-ative to maintain-a` :source 0f pressure fluid for.operationof .said motive unit, a controlvalve in said system normallyblocking admission of operating uid `to `said motive unit,` a pair offluid pressure operable devices, each-.mechanically :connected to saidcontrol valve to` admit operatingfluid `to `said motive unit, one of:said devices, being arranged for operation by failure ofA the oil pumpto maintain, predetermined lubricating oil pressuregthe other-beingarranged for operation by excessive oil pump suction.

3. In and for an internal combustion engine having a lubricating oilpressure maintaining system the pressure of which varies with enginespeed, a hydraulic relay speed governor for the engine, a speed settingservo mechanism for the governor including a servomotor element arrangedto adjust the engine speed through the intermediary of the governor fromlow through a range of speed settings, means to cause shutdown of theengine through the intermediary of `the governor, pressure-sensitivemeans adapted for connection with the lubricating system and operable inresponse to an undesirably low pressure condition thereof to initiateoperation of the engine shutdown means, and a device connected foroperation by the speed setting servomotor element and acting to opposesaid operation of the pressure-sensitive means with a force whichincreases solely as a function of speed setting servomotor elementposition from low toward high speed settings.

4. In or for an internal combustion engine having a lubricating oilpressure maintaining system the pressure of which varies with enginespeed, a hydraulic relay speed governor for the engine, a speed settingservo mechanism for the governor including a servomotor element arrangedto adjust the engine speed through the intermediary of the governor fromlow through a range of speed settings, means to cause shutdown of theengine through the intermediary of the governor, pressure-sensitivemeans adapted for connection with the lubricating system and operable inresponse to an undesirably low pressure condition thereof to initiateoperation of the engine shutdown means, a spring arranged to oppose theaction of lubricating oil pressure on said means, and a deviceoperatingly connecting the speed setting servomotor element to saidspring and operating to increase the effective force of the spring as afunction of increased speed setting positions of the servomotor element.

5. In combination with a hydraulic relay engine governor having a speedconscious pilotvalve-operating mechanism and power piston actuatedthereby for engine fuel adjustment and fluid operated servo system withits servomotor acting on the speed conscious mechanism for engine speedadjustment, a source of fluid pressure for said speed setting servosystem, the relay valve of the system being subject to rapid adjustment,means embodied in the relay valve normally to cause spurtwise controlledrate fluid movement in respect to the speed setting servomotor; engineshutdown means actuated by the speed-setting servo motor in onedirection of its operation, and a device -actin'gon the relay `valve ina manner'to overcome lits spurtwise fluid controllinga-ction whereby' tocause rapid' rate flu-id movement therethrough for the shutdownactuating operationof `the speed setting servoinotor. 1

6; In combinationwith an internal combustion-f engine fuel* 4regula/tinghydraulic relay rgovcrnorA mechanism for engine-generator locomotiveservice, la operated speed Ysetting servo mechanism having a servomo-toroperating o n a speed-sensing means -of the governor mechanism and apilot -'valve including a `ported `sleeve and plunger with fluidconnections to the servomotor, signal operated rapid-motion vmeans' toVrelatively adjust the sleeve and plunger axially for causing speedsetti-ng movements of the servo- Inotor from low speed through a desiredoperating range, said sleeve being continually rotated, porting meansrendered operative by said rotation for eifecting spurtwise flow andcontrolled rate operation of the servomotor in two directions, fluidoperated engine shutdown. means in the governor mechanism and actingtherethrough to stop the engine, porting means rendered operative bysaid rotation to supply duid spurtwisc for operating the engine shutdownmeans, pressure sensitive means responsive to an undesired condition ofthe engine and including a valve normally blocking the supply ofspurtwise uid to the engine shutdown means, fluid connections betweensaid porting means and valve last identified for circumventing orby-passing the spurtwise fluid as supplied to said valve, acircumventing valve in said connections and means connecting the same tothe speed setting servomotor so that the circumventing valve is openedwhenever said servomotor is in a higher than said low speed position.

7. In an internal combustion engine governor mechanism for enginegenerator locomotive service, a hydraulic relay speed governing unithaving fuel regulating means and speed conscious mechanism including arelay valve actuating said means, a hydraulic speed setting servomechanism adapted for rapid action through remote control and operatingon the speed conscious mechanism, hydraulic shutdown means, a pilotvalve for the speed setting servo mechanism having continuallyrelatively rotating telescoping parts including a plunger and sleevewhich are relatively movable aXially to normal positions for controllingthe speed setting operation and similarly to a wholly abnormal positionand in that case being operative to actuate the shutdown means, ashutdown motive unit for operating the pilot valve plunger to itsabnormal position, fluid control spurt determining ports in two of saidrelativelyT rotating valve parts for supplying fluid at a controlledrate for delayed operation of the shutdown motive unit when the speedsetting servo mechanism is in a low speed setting position, a valveblocking admission of such 'controlled rate duid to said motive unit,valve means `controlled by the speed setting servo mechanism when inhigher speed setting positions to circumvent the controlled rate fluidsupply to the blocking valve, and means responsive to an undesiredcondition of the governed engine and arranged for opening said blockingvalve when such condition obtains.

8. In and for a hydraulic relay governor in fuel regulating relationshipto an internal `combustion engine, said governor having a speed settingmeans and hydraulically acting engine shutdown mechanism, a speedsetting fluid operated servo system including a speed setting servomotoracting on the governor speed setting means and a pilot valve forcontrolling the servomotor, means for effecting predetermined valvingmovements of the pilot Valve in opposite directions for speed setting,valve means operated by the pilot valve when the latter is movedadditionally in one d1- rection beyond such predetermined movement foractuating the shutdown mechanism, a fluid actuated shutdown motive unithaving an operating part arranged additionaly to move the pilot valve asstated, a valve system operable to supply said motive unit withoperating riuid at a lcontrolled rate, valve mechanism in said systemand operating means therefor responsive to an undesired condition of thegoverned engine, said valve mechanism rendering the system operative tov apply the controlled rate iiuid to said motive unit, and latchingmeans acting on said operating part of the motive unit to retain saidpilot valve in shutdown actuating position.

LLOYD JACKSON MOULTON.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,967,851 Wilson July 24, 1934 2,344,308 K-aln Mar. 14, 19442,542,765 Gillespie Feb. 20., 1951 FOREIGN PATENTS Number Country Date233,432 Great Britain May 8, 1925

